I submitted a fake solution during contest.(Round 631 div2) I figured it out and spent half an hour to fix it. But I find that the fake solution could pass system tests, WHY? Hacking it doesn't even need special cases but simply 10 2 9 2 will work. Also 6 3 4 1 1 will work to. Maybe the system test isn't that trustworthly? submission: 75417494 You can check my code and check that there is nothing "made to be hacked".